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Scientists have created what they say is the world's smallest untethered flying robot, by taking a unique approach to its design. To minimize size and weight, they've moved the bot's power and control systems out of its sub-centimeter-wide body.

Measuring just 9.4 mm in width and tipping the scales at 21 mg, the robot is being developed by Prof. Liwei Lin and colleagues at the University of California, Berkeley. The bot's 3D-printed polymer body consists of a four-bladed horizontal propeller, encircled by a "balance ring." Protruding up from the center of the propeller is a small vertical ring that holds two puck-shaped neodymium permanent magnets – each one is 1 mm wide by 0.5 mm thick.

The robot is powered and steered by an alternating magnetic field which is externally generated along a single axis. As the bot's two magnets are simultaneously attracted to and repelled by that field, they cause the attached propeller to spin, creating lift. Once the robot has become airborne, its balance ring adds rotational inertia, producing a stability-boosting gyroscopic effect.

Uniformly increasing or decreasing the strength of the magnetic field moves the robot up or down by causing it to spin faster or slower, respectively. And by varying the magnetic field's strength over horizontal distance, it's possible to move the bot forward, backward, or sideways accordingly.

#Technology
#Robots

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